I recently bought a nookcolor, and after discovering it could get more memory via mSD card, i bought a 2G sandisk Micro SD card. I read the instructions on how to insert it, but it wont "click" in, I push the card in correctly, but it comes back out, meaning it can be slid out at anytime. Is it Possible to replace the mSD jack?

No, the "jack" can not be replaced but since you just bought the NC you can take it to a B&N store and have them try to determine what's wrong. If they can't get the card to work for you they can replace the unit under warranty.